COS-B observations of pulsed gamma -ray emission from PSR 0531+21 and PSR 0833-45.
Bignami, G. F.; Hermsen, W.; Masnou, J. L.; Boella, G.; Bennett, K.; Buccheri, R.; Lichti, G. G.; Mayer-Hasselwander, H. A.; Paul, J. A.; Scarsi, L.; Swanenburg, B. N.; Taylor, B. G.; Wills, R. D.; Kanbach, G. G.
Netherlands, Italy, Germany, France
Abstract
Summary. CO S-B has performed detailed measurements of the high-energy y-ray emission from the Crab and Vela pulsars. The two pulsars exhibit very similar y-ray light curves, both with narrow peaks of roughly equal intensity separated by 0.42+0.03 of the period. The fractions of the y-rays of energy >50 MeV which are pulsed have 2a lower limit of 78 % in the case of PSR 0531+21 and 91% for PSR0833-45. The differential spectrum of PSR 0531+21 can be represented by (2.4 04)10 ?E (2.11O.3) in the range 50 MeV to 4 GeV, while it is difficult to reconcile the spectrum of PSR 0833-45 with a single power law over the same energy range. Key words: COS-B y-ray astronomy - pulsars Crab Vela